body{
    background: url("../img/image1.jpg");
    animation-name:bg;
    animation-duration:20s;
    /*变换时间*/
    animation-delay:2s;
    /*动画开始时间*/
    animation-iteration-count:infinite;
    /*下一周期循环播放*/
    animation-play-state:running;
    /*动画开始运行*/
}
@keyframes bg
{
    0%   {background:url("../img/image1.jpg");}
    34%  {background:url("../img/image2.jpg");}
    67%  {background:url("../img/image3.jpg");}
    100% {background:url("../img/image1.jpg");}
}
.form{background: rgba(255,255,255,0.7);width:500px;margin:220px auto;}

/*阴影*/

.fa{display: inline-block;top: 27px;left: 6px;position: relative;color: #ccc;}
input[type="text"],input[type="password"]{padding-left:26px;}
.checkbox{padding-left:21px;}
